Washington State may have one of the lowest overall tax burdens in the country, but its poorest citizens pay more than residents of any other state.

The poorest 20 percent of Washington residents pay 16.9 percent of their income in taxes, while the top 1 percent (with an average income of more than $1.1 million) pays just 2.8 percent of its income, according to a new study from the left-leaning Institute on Taxation and Economic Policy.

The study found that tax policies in every state impose higher effective tax rates on poor families than on their richest residents. The difference is greatest in states that do not levy a personal-income tax, and rely heavily on sales and excise taxes, which take a bigger relative bite out of the budgets of the poor.

Florida ranked second in taxation inequality; taxing the poorest 20 percent of residents at a rate of 13.2 percent of income, and its wealthiest 1 percent at 2.1 percent of income.

Nationwide, the poorest 20 percent pay 11.1 percent of their incomes in state and local taxes; middle class residents pay an average 9.4 percent of their income in taxes; and the wealthiest 1 percent pay 5.6 percent of their income in taxes, according to the report.

New York and the District of Columbia are among the states with a close-to-flat tax system, thanks to their use of a refundable earned-income tax credit, and an income tax with high top tax rates and few tax break for upper income taxpayers, and property tax breaks for low-income residents.